This invention relates generally to wireless communication systems and, more particularly, to a system for determining location information using radio frequency identification (RFID) devices.
Different systems and technologies are known for use in determining location information. For example, current technology provides for locating personnel in a building based on global positioning system (GPS) and/or radio triangulation methods. These methods generally can provide accurate location information. However, in buildings, these methods provide limited accuracy due to marginal signal strength and multipath reflections.
In order to locate, for example, a person using a GPS or radio triangulation method, the person must be carrying the GPS or radio device and that device must be operating. In emergency or catastrophic situations, for example, such as a fire, explosion, etc. in a building, there is a high probability that the GPS or radio device will be destroyed or rendered inoperable as a result of the conditions or effects in the post event disaster zone. Additionally, there is a possibility that during the catastrophic event and because of, for example, panic, a person may lose the GPS or radio device. In these situations, time is of the essence and reliable and accurate location information would increase the likelihood of locating a person trapped in a building after a catastrophic event. Further, it is typically not possible to determine the previous location for the person having the GPS or radio device because the information is not stored for later access, except maybe within the device itself. In particular, location information typically is not wirelessly transmitted and stored, but usually is stored, if at all, by downloading, for example, to a computer at a time much later than the actual use.
Thus, although GPS or radio triangulation systems are capable of providing reliable location information, in some situations or conditions, the information may not be reliable or may not be available. Further, these systems do not allow access to up to date archive location information.